Visual Snow Syndrome, Migraine, Healthy
Conditions
Keywords
Visual Snow Syndrome, Visual Snow, Migraine, Floaters, Palinopsia, Photophobia, Nyctalopia, Entoptic phenomena, Visual trailing, Adaptation, Magnetic resonance spectroscopy, MRS, Magnetic resonance imaging, MRI, University of Minnesota, Afterimages, Poor night vision, Light sensitivity, Persistent positive visual phenomena, Static
Brief summary
The goal of this study is to learn more about the brain pathways and activity involved in creating Visual Snow Syndrome (VSS). The main questions it aims to answer are: * Does VSS arise from spontaneous activity in brain pathways? * Where in the brain does the activity contributing to VSS arise? * How does brain activity contribute to VSS? Participants will: 1. Undergo assessments and questionnaires to understand visual and mental symptoms, cognitive, and sensory function. 2. Make visual judgements based on images presented to them both inside and outside a magnetic resonance imaging (MRI) machine. 3. Undergo scanning of their brain while inside of an MRI machine.
Interventions
BEHAVIORALVisual Adaptation
Presentation of visual stimuli to quantify the appearance of visual snow or its effects in the visual system of the brain.
BEHAVIORALAssessments and Questionnaires
Administration of clinical assessments and questionnaires to gather information about visual and mental symptoms, cognitive, and sensory function.
DEVICEFunctional Magnetic Resonance Imaging (fMRI)
7 tesla fMRI data will be acquired during visual paradigms designed to measure neural responses with and without adaptation.
DEVICEMagnetic Resonance Imaging (MRS)
7 tesla MRS data will be acquired to quantify the concentrations of different brain chemicals in brain regions including visual cortex.
Sponsors
National Institutes of Health (NIH)
Mayo Clinic
National Eye Institute (NEI)
University of Minnesota
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
Inclusion criteria
for People with Visual Snow Syndrome: * Between the ages of 18 and 60 years old * Normal (20/25 or better in each eye) or corrected-to-normal vision (MR-compatible glasses will be provided as needed) * Ability to comply with study instructions * Individuals who have a current diagnosis of VSS from a neuro-ophthalmologist or meet diagnostic criteria of VSS (experience of dynamic dots across the visual field persisting longer than 3 months and at least 2 of the following additional visual symptoms: palinopsia, entoptic phenomena, trails behind moving objects, photophobia, or nyctalopia) * Individuals living in Minnesota within 2 hours of the study site Inclusion Criteria for Non-snow Controls: * Between the ages of 18 and 60 years old * Normal (20/25 or better in each eye) or corrected-to-normal vision (MR-compatible glasses will be provided as needed) * Ability to comply with study instructions * Individuals living in Minnesota within 2 hours of the study site
Exclusion criteria
for People with Visual Snow Syndrome: * Not being fluent in English or another language for which interpretation/translation services are available * A diagnosed or self-reported intellectual disability * Current substance dependence (besides nicotine), or drug dependence with tolerance or withdrawal within past 12 months * Hallucinogenic substance use within the past 12 months or hallucinogenic substance use within 12 months prior to onset of VSS symptoms * Severe central nervous system disease * Head injury with skull fracture or loss of consciousness for more than thirty minutes * Presence of a physical problem that would render study measures difficult or impossible to administer or interpret (e.g., visual field loss) * Age less than 18 years or greater than 60 years * MRI exclusions (for MR visits only): * Metal in the body that cannot be approved by the CMRR safety committee * Pregnancy * Conditions that affect neuro-hemodynamic coupling * Claustrophobia * Inability to lie still for at least an hour * Weight in excess of 440 lbs * CT scan exclusion only: Research-related radiation exposure within the last 12 months * Any vision anomaly aside from VS or refractive error (e.g., strabismus/ crossed eyes, lazy eyes, color blindness) * Current psychotic episode
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Psychophysical Adaptation Task Performance | 1.5-2 hours per session, with experiments divided across multiple (e.g., 3) sessions | Visual tasks will consist of perceptual judgments following adaptation (e.g., subject will report when internal or external / simulated visual snow appears the same on the left or right side of the screen). Measures will be compared for visual target stimuli in different task conditions and experiments, with the goal of understanding the neural basis of visual snow. |
| Functional Magnetic Resonance Imaging (fMRI) Measures | 1-2 hours per session, with experiments split across multiple (e.g., 3) sessions | 7 tesla fMRI data will be acquired during visual paradigms designed to measure neural responses with and without adaptation. FMRI data will be processed and analyzed to quantify the effect of adaptation across different regions in visual cortex. |
| Magnetic Resonance Spectroscopy (MRS) | 1-2 hours | 7 telsa MRS data will be acquired to quantify the concentration of different brain chemicals in brain areas including visual cortex. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Clinical Symptom Scores | 1-2 hours | Measures of visual and mental symptoms, cognitive, and sensory function (e.g., Visual Snow Questionnaire), will be collected using self-report and interview methods. Scores will be compared across groups to differences in visual and mental symptoms in people with and without visual snow syndrome (VSS). |
Countries
United States
Contacts
Primary ContactMichael-Paul Schallmo, Ph.D.
Backup ContactHannah Moser, Ph.D.
Outcome results
None listed